In Assassin's Creed Odyssey, the game begins on the Greek island of Kephallonia.
Kephallonia is the starting region for the player character, either Kassandra or Alexios. The opening storyline introduces the protagonist's life as a mercenary, their relationship with Markos, and the early choices that begin the larger family-centered journey. The island contains settlements, wildlife, quests, and ancient ruins that teach the game's exploration and combat systems.
The name is also written Cephallonia in some English contexts, reflecting different transliteration traditions for the Greek island of Kefalonia. Assassin's Creed Odyssey uses the form Kephallonia in its game world and localization.
Crete, Delos, and Naxos are real Greek islands, and several Greek locations appear later in the game. They are not the island where the opening chapter takes place. Odyssey's wider map represents the Aegean world during the Peloponnesian War.